This invention relates to new and useful benzothiazine dioxide salts. More particularly, it is concerned with certain novel crystalline, non-hygroscopic, water-soluble salts of N-(2-pyridyl)-2-methyl-4-hydroxy-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide, which are of especial value in view of their unique combination of chemotherapeutic and physical properties.
In the past, various attempts have been made to obtain new and better anti-inflammatory agents. For the most part, these efforts have involved the synthesis and testing of various steroidal compounds such as the corticosteroids or non-steroidal substances of an acidic nature such as phenylbutazone, indomethacin and the like, including a new agent known as piroxicam. The latter substance is a member of a class of anti-inflammatory 4-hydroxy-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxides described and claimed in U.S. Pat. No. 3,591,584. However, in the continuing search for improved anti-inflammatory agents, there is a definite need for anti-arthritic agents having high water-solubility and other desirable properties and especially adapted for oral, topical or parenteral administration.